Gas engine combined with a scavenging pump



June's; 1925.

E. ARENDT GAS'ENGINE CQMBINED WITH A SGAVENQING PUMP Filed March 9. 1925Patented .lune 9, 1925.

UNITED STATES PATENT OFFICE.

ERICH ARENDT, OF SAARBRU'CKEN, GEBMANY, ASSIG'NOR TO EHRHARDT & SEHMERAKTIENGESELLSCHAFT, OF SAARBRUCKEN, GERMANY, .A CORPORATION OF GER- MANY.

Application led March 9, 1925. Serial No. 14,251.

T o all whom t may concern: i

Be it known that I, ERICH ARENDT, a citizen of Germany, residing atSaarbrucken, in the State of Saargebiet, Germany, have invented certainnew and useful Improvements in Gas Engines Combined with ScavengingPumps; and I do hereby declare the following to be afull, clear, andexact description of the invention, such as will enable others skilledin the art to which it appertains, to make and use the same.

This invention relates to the combination of a gas engine with a pumpfor scavenging and charging purposes, the piston of the pump beingmounted on the piston rod of the rearmost gas engine cylinder. A knownfeature in machines of this kind consists in arranging the scavengingpump piston so that it supports the rear end of the piston rod. A greatdisadvantage of this arrangement in practice is however that, inconsequence of the copious lubrication required for the rubbing surfaceof the scavenging pump piston, a large amount of oil is carried by thescavenging air into the power cylinder of the gas engine and thereproduces undesirable eects.

Hence it has been found necessary in the operation of such machines tolubricate the scavenging pump piston as little as possible.

The object of the present invention is to meet these requirements andthis is accomplished by arranging the scavengingpump piston on thepiston rod so that it is practically held suspended in the scavengingpump cylinder, the piston rod itself being supported by a supplementalbearing which is located between the scavenging pump Aand gas enginecylinder, which bearing is movable and adjustable on a slide bed or thelike to a position away from the gas-engine cylinder.

By this arrangement the desiredshortness of the machine is maintained,because the piston support can easily be placed between the scavengingpump and gas engine cylinders without taking up much space.

By this arrangement it is furthermore rendered possible in almost allcases to add a scavenging pump to an existing machine.

When the adjacent stuffing box of the gas engine cylinder has to beremoved itis necessary to shift this supplemental piston rod support. Toenablev the stuliing box to be conveniently inspectedand easily removedwithout employing special devices for supporting the piston rod the saidpiston rod support is arranged, as stated, so that it can be shifted ona slidebed in the longitudinal direction of the piston. The machiningoperations in the workshop and the assembling of the machine arerendered yas cheap and convenient asY possible by supporting the pumpcylinder' in a curved bed shaped in the form of a section of a cylinderthat is concentric to the longitudinal axis of the machine. Inaccordance with the invention the piston rod support or bearing isbedded and fixed in a prolonged section of -this curved bed. By thisarrangement it is possible to shift both the scavenging pump cylinder'and the piston-rod support along the same surface or slidebed when thestung box of the gas engine cylinder is to be made accessible.'

In the preferredembodiment of theinf vention, the piston` rod support orbearing may be directly attached to the scavenging pump cylinder' or itscover. In this construction the supplemental piston rod support and thepump cylinder are moved when the scavenging pump cylinder is shifted.

To enable the scavenging pump cylinder and the piston rod supportconnected therewith to be thus shifted in a most convenient manner thepiston rod and scavenging pump cylinder are arranged to be temporarilybut rigidly connected to each other by a screw coupling vmember or thevlike, so that the pump cylinder and the piston rod support connectedtherewith can be conveniently shifted through the medium of the gasengine piston rod by means of the usual flywheel stepping (starting)mechanism, i. e., the lever and pawl arrangement that cooperates withratchet teeth on the flywheel.

The invention is shown by way of example in the drawing in whichj Fig. lis a longitudinal section of a part vof the gas engine cylinder with myimproved scavenging pump attached to the end thereof.

Fig. 2 is a similar view showing armodiflcation in which the pistonsupport or bearing is directly attached to a cylinder cover of thescavenging pump.

Fig. 3f is the cross section through a scavenging pump cylinder. In thetype of machine shown in Fig. l the supplemental piston support Z hasthe form of a pedestal which is located in the space between the pumpand engine. a is the'rear portion of a v gas engine cylinder and 0 isthe scavenging pump cylinder. The piston rodVV g supported bythe'bearingl d passes through a stuiiing box e in the cylinder cover ofthe gas engine and atqits rear orfree end it carries the scavenging pumppiston h. In a machine in which the piston rod bearing d is larranged tobe shifted lengthwise so as to provide for an easyaccess to the stuffingbox, the scavenging pump cylinder c is also arranged to be 'snif/tedlengthwise. To this end there is provided a common guide surface or bedvf, (Fig. The piston rod support or bea-ring rl' mayv be directlyconnected to the scavenging pump as shown in Fig. 2, in which it isattached to the cylinder cover, the scavenging pump cylinder beingarranged to be shifted in a guide or slide bed fV so as to make thestuffing box z' easily accessible. The piston rodv support 0l isarrangedto take the entire weight of the scavenging pump piston L, i. e.it holds it practically suspended in the pump cylinder c so that it doesnot touchV its wall, friction with this wall arising only through thepiston packing ring. Y

' To enable the pump cylinder c and the pistonfrxod support Z to beshifted on their be'dlin the most convenient manner a screw couplingmember may be provided for effecting a rigid connection between thepis'- ton rod g andthe scavenging pump cylinder c. -When such rigidcoupling is effected, as shown in Fiff. 2, and the pump cylinder isunscrewed, i. e., loosened from the slidebedbase, the bearing d and pumpcylinder c can be conveniently shifted as a unit'in any suitable manner,away from the adjacent end of the gas engine cylinder, thereby renderingit convenient to get access to the stuffing-box thereof. As a simplemeans for thus sliding the pump cylinder and the piston-rod bearing awayfrom the gase engine cylinder, I may use the well-known lfly-wheelstepping (starting) mechanism heretofore referredto, as by'rotating thecrank-shaft of the engine, the piston-rod will be thrustv forward towardthe outer end of the pump cylinder, carrying with it the pump cylinderand its attached bearing d.

While speciii'c forms of the invention are illustrated in the drawingsand described hereinbefore it is obviousthatmany changes may be madewithout departing from the scope and spirit of the invention.

claimpl: in 'a gas engine combined with a scavenging pump, an enginecylinder, a pump cylinder, a piston rod extending into both cylinders, apump piston which 1s carried and whose entire weight 1s substantiallyVtaken by said rod, and a supplemental bearand held suspendedin Vthepump cylinder by said rod, and a bearing between the pump and the enginecylinder which supports said rod, said bearing-being movable in thedirection of the axis of thel engine. Y

3. In a gas engine combined with a scavenging pump, an engine cylinder,a pump cylinder, a piston rod extending into both cylinders, a pumppiston which is carried and whose entire weight is substantially takenby said rod, and a bearing between the pump and the engine cylinderwhich supports said rod and is adjustable in the direction of movementof said piston to permit access to the adjacent stufiing-box of the gasengine.

4. In a gas engine combined with a scavenging pump, an engine cylinder apump structure embodying a movable cylinder, a piston rod extendinglinto both said cylinders through a cylinder cover carried by each ofYsaid; cylinders, a pump piston which is carried and whoseentire weightis substantially taken by said rod, and a bearing which supports saidrodand is attached to the pump cylinder so asV to be movable there.:

withto a-point away from the adjacent end of the engine cylinder.

5. In a gas engine combined with a scavenging pump, an engine cylinder,a pump cylinder, a piston rodextending intovboth said cylinders throughcylinder covers belonging to said cylinders, a pump piston which iscarried and whose entire weight is substantially taken by said rod, anda bearing which supports said rod and is' attached directly to thecoverof the pump cylinder;

6: In a gas engine combined witha scavenging pump, an engine cylinder, aslide bed attached ,to the engine cylinder, a pump cylinder slidablymounted on said slide bed,

a piston rod extending' in-to both'said cylinders, apuinp piston whichis carried and whose entire weight is substantially taken by said rod,anda bearing likewise Vslidably mounted on said slide -bed and arrangedto support' said rod.

7. In a gas engine .combined with a' scavenging pump, an enginecylinder,a slide-bed attached to said engine cylinder, av pump cylinder slidablymountedon said `slide bed, a pistonrod extending into both saidcylinders, a pump piston which is-'carried and whose entire weight 'is`substantially taken llt by said rod, a bearing likewise adjustablymounted on said slide bed and arranged to support said rod, and aconnecting member adapted to rigidly connect the pump piston with thepump cylinder, so that axial movement of the piston-rod will move thepump cylinder and said connected bearing.

In testimony whereof ax my signature 1n presence of two wltnesses.

ERICH ARENDT.

Witnesses:

WLAD ENDELY, ROY V. Fox.

